Thermally insulated enclosures are useful in many contexts. For example, the use of thermally insulated enclosures for HVAC equipment (e.g., heat exchangers, compressors, blowers, filters, fans, motors, cooling elements, heating elements, humidifying elements) is commonplace. Other types of thermally insulated enclosures such as walk in coolers and freezers often need to be constructed rapidly and with an ability to be readily knocked down. Thermally insulated enclosures are often constructed with panels filled with insulation to minimize the transmission of thermal energy from the interior to the exterior of the enclosure. Typically, the panels include inner and outer (first and second) panel members of metal that are joined together to form a volume that receives the insulation. The panel members can be connected together using plastic fasteners and/or gaskets to reduce thermal transmission. However, the inner and outer panel members are often difficult to manufacture, and it can be difficult and time-consuming to attach the panel members to each other to form the insulated enclosure.